Disclosures in hitherto secret papers released at the National Archives under the 30-year rule are extraordinarily pertinent now. Despite Nott's claim about the prevailing view in Thatcher's government 30 years ago, the government built a four-boat Trident submarine fleet, designed and assembled new warheads, and leased the missiles from the US.

Today, we do not know how many ministers are questioning the plan to replace the existing Trident system. We may have to wait for 30 more years to find out. It is known that senior members of the armed forces have serious doubts about the wisdom of investing tens of billions in a new nuclear weapons system that is widely regarded as irrelevant to the immediate interests and pressing needs of Britain's armed forces. Whenever they are asked about Trident, they dodge the question, saying it is a "political" matter. (They say the same about plans to build two large new aircraft carriers for the Royal Navy, the other expensive item digging an enormous hole in the defence budget.)

Even Tony Blair, in his autobiography, A Journey, described Trident's purpose as "non-existent in terms of military use", remarking: "Its expense is huge." In 1981, the government was advised by Ministry of Defence experts that the initial cost of acquiring Trident would be £5bn. It cost twice as much.

Earlier this year, the MoD quietly acknowledged that the cost of a new fleet of Trident nuclear missile submarines – excluding the the missiles and warheads that would go on them – would amount to £25bn by the time they were built. That is more than double the existing estimates.

Thirty years ago, Lord Armstrong, the cabinet secretary, told his prime minister that she need not worry about not telling all members of the government about nuclear weapon projects, as there were precedents for not doing so, not least from the previous Labour governments of Harold Wilson and Clement Attlee. Things are a bit different now. Blair published a white paper on Trident and the Lib Dems have questioned the need to replace the UK's existing Trident nuclear force by a like-for-like system.

But the debate remains stifled. Trident was excluded from last year's strategic defence and security review. As part of the coalition agreement, the Lib Dems were offered a Trident "value for money" review. It is little more than a fig leaf. On the eve of the parliamentary Christmas recess, defence minister Peter Luff told MPs the review would "constitute a full and frank exploration of the alternative systems at a highly classified level". Nick Clegg would see it. But, said Luff, "there are no plans to publish either the report or the information on which it draws".

It is clear the review is being designed to show that any alternative nuclear weapons systems to Trident would not save money and would be less effective. In a Whitehall document on the Trident review, released under the Freedom of Information Act, the entire section titled "Overall financial position" has been suppressed.

Despite the continuing crisis facing the defence budget, with commitments costing much more than the MoD can spend, the review is most unlikely to contemplate any serious scaling down of the government's nuclear ambitions. Abandoning nuclear weapons altogether will remain absolutely taboo.

The coalition has agreed to postpone a final decision on Trident until after the next general election, due in 2015. Luff admitted to Labour MP Jeremy Corbyn, a long-standing opponent of nuclear weapons, that the government had already agreed to spend £5bn on a new Trident system, most of it on a new submarine design. Some of the money has gone on research at the Atomic Weapons Establishment at Aldermaston into the "capability of a new warhead".

Britain, meanwhile, is also collaborating with the US on plans to replace nuclear warhead components. Corbyn asked the government whether Britain was "walking – indeed, sleepwalking – into a massive expenditure" on Trident. There are many in Whitehall asking the same question, albeit very quietly.